Preheating in yarn texturing



y 7, 1969 E. J. BERGER JR 3,445,996

PREHEATING IN YARN TEXTURING Filed May 8. 1967 EMIL J. BERGER, JR.

ATTORNEYS.

73 INVENTOR.

3,445,996 PREHEATING IN YARN TEXTURING Emil J. Berger, Jr., Wayne, Pa., assignor to Turbo Machine Company, Lansdale, Pa., a corporation of Pennsylvania Filed May 8, 1967, Ser. No. 636,814 Int. Cl. D01h 13/26, 13/28, 13/04; D02g 3/02 US. CI. 57-34 5 Claims ABSTRACT OF THE DISCLOSURE In a system for texturing yarn using a false-twisting technique, two ends of multi-filament yarns of heatsettable material are pulled by delivery rolls, with the filaments untwisted, substantially flat, substantially parallel to each other, and under controlled tension through an elongated arcuate contact heater to preheat the yarn filaments. The two ends of preheated untwisted yarn then pass through a multi-stage device wherein the ends of yarn are transformed progressively in stages from untwisted condition into a two-ply twisted yarn. The twoply twisted yarn is then further heated, and then passed through a cooling zone to set the twist. The ends of yarn are then separated and passed through the delivery rolls to separate take-up rolls. In the preferred embodiment, the single ends of yarn are preheated untwisted in the same arcuate contact heater in which the twisted yarn is heated. The method and apparatus are also applicable to texturing a single end of multi-filament yarn.

BACKGROUND OF THE INVENTION Field of the invention This invention relates to apparatus and method for texturing heat-settable yarn using false-twist methods.

Description of the prior art Summary of the invention The present invention is directed to a method and apparatus for teXturing yarns, particularly multi-filament heat-settable yarns. The invention enables the yarns to be run through the texturing apparatus at substantially higher rates of speed than have heretofore been permissible. This desirable result is achieved by preheating two single ends of yarn under tension in untwisted substantially fiat condition, then in progressive steps smoothly twisting the heated filaments of the two ends together into a two-ply yarn, further heating the twisted two-ply yarn, cooling the yarn to set the twist, and finally separating and packaging the individual yarn ends.

In the preferred embodiment, an elongated arcuate contact heater is provided having two parallel grooves. The two ends of multi-filament yarn are pulled under tension, untwisted, and substantially flat and parallel, through the heater in contact with the arcuate surface of the first groove. Upon leaving the first groove, the two ends of heated yarn filaments pass through a twistbarrier device into the twist or texturing zone. The twistbarrier device is preferably of an improved type which inhibits, in a series of stages, the twist from running back upstream into the first heater groove. After leaving the twist-barrier device, the two ends of yarn are pulled, twisted together and under tension, through the same nitecl States Patent 0 heater in the opposite direction, in contact with the arcuate surface of the second groove.

It is important to note that when the two ends of multifilament yarn are pulled, untwisted and substantially flat and parallel, through the heater in contact with the arcuate surface of the first groove, the yarn ends absorb a substantially greater amount of heat than they would absorb if the yarns were in twisted condition. This is particularly so in the case of the larger denier yarns. For, when the yarn ends are untwisted, fiat and separate, each filament of each end maintains substantially continuous contact with the arcuate surface of the heater as the ends are pulled therethrough. In contrast thereto, when two multi-filament yarn ends are twisted together to form a two-ply yarn, each filament follows a helical path and each filament has considerably less than continuous surface contact with the arcuate heater. Some of the filaments may not make contact at all during their passage through the contact heater. Thus, a yarn end of untwisted, substantially fiat bend of filaments absorbs substantially more heat than does the same yarn end after being twisted together with another yarn end. It has been found that preheating the yarn ends prior to twisting enables the permissible running speed of the texturing apparatus to be very substantially increased.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a diagrammatic illustration of a texturing system utilizing the preheating technique of the present invention;

FIG. 2 is a detail view, enlarged and in section, taken along the line 11-11 of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT The drawing illustrates one form of texturing apparatus embodying the present invention. The novelty resides in preheating the single ends of yarn under tension before they are twisted together by a progressive or multistage type of assembly device. This allows the texturing equipment to be run at higher speeds.

In the texturing apparatus illustrated in the drawing, the heater is vertically disposed, and the yarn paths are primarily vertical. In the drawing, the yarns move downward toward the floor, then upward toward the ceiling, then downward toward the floor, then upward again toward the ceiling, and then downward again toward the floor. This arrangement is advantageous in that considerably less floor space is required and the cost chargeable to the texturing operation is reduced. The arrangement, however, requires reasonably careful adjustment of the cornering or guide rollers about which the twisted yarn ends are pulled in the texturing zone.

In the drawing, two single ends of yarn 12 and 13 are shown supplied by separate supply packages 10 and 11. The yarn ends 12 and 13 are shown passing downwardly from the supply packages 10 and 11 through a pretwister 14, around a pair of guide rollers 15, then up through guide means 16, over and about a yarntensioning device 17, over the guide roller 19, down through heater 30 along a first arcuate groove 31 thereof, through a twist barrier device B disposed below the heater 30, then upward as a twisted two-ply yarn 18 through the heater 30 along a second arcuate groove 32 thereof. The twisted two-ply yarn then passes through suitable guide means not shown, over the left corner roll 42, the center corner roll 43, and the right corner roll 44, then down tothe separation device S. At the separation device S, the two ends of the two-ply yarn 18 are separated at pins 61, 62 into single ends 12, 13 which pass through the guide means 63 and 64, down through pairs of conical nip rolls 65 and 66, and then through the reciprocating traversing means 71, 72 to the take-up rolls 73 and 74. Between the upper end of the heater 30 and the separation device S, the two-ply twisted yarn 18 is cooled and thetwist is set.

The single ends of yarn 12 and 13 comprise wholly or predominantly hea -settable yarn filaments, such as continuous filaments of synthetic thermoplastic material. Examples of suitable materials are nylon (polyhexamethylene adipamide), Dacron (polyethylene terephthalate), polypropylene, co-polymers of vinyl chloride, and others.

At start-up, the single ends of yarn 12 and 13 are pretwisted together, as by a form of pretwist device 14 sh wn and described in Carruthers US. Patent 3,237,391. This puts a predetermined number of turns per inch into the yarns in the texturing zone, which extends from the twistbarrier device B to the separation device S. The twistbarrier device B may take a number of forms, but preferably takes one of the various forms of two-stage or multi-stage twist-barrier device shown, described and claimed in the copending application of Emil I. Berger, Jr. and William Kirk Wyatt entitled Yarn Assembly Apparatus for False-Twisting Yarns filed May 8, 1967, Ser. No. 636,976, and assigned to the same assignee. In the drawing of the present application, the device B is shown to comprise a pair of cross rollers 81, 82, mounted for free rotation in block 83, forming opposed crotches through which the two ends of yarn 12, 13 are pulled. The filaments of the two-ply yarn 18 on the downstream side of the device B move along a helical path, and have a component of movement which is axial with respect to both the upper and lower of the crossed rollers 81 and 82. This introduces frictional components at both the upper and lower rollers, and this tends to inhibit, in stages, passage of the twist through the device B, but without putting high-friction forces into the yarn, because of the rotating rollers. As a result of the twist-inhibiting action of device B, there are considerably fewer turns per inch between the texturing zone side of the upper roller 81 and the lower roller 82, still fewer turns per inch between the lower roller 82 and the feed side of the upper roller '81, and substantially no twist above the upper roller 81 on the feed-in side.

In the illustrated apparatus, the yarn is pulled through the texturing apparatus by two pairs of conical nip rolls 65 and 66. The conical rolls 6S and 66, the drive means therefor, the take-up rolls 73 and 74, the reciprocating traversing guide means 71 and 72, and the separating device S, may, if desired, be similar to that shown and described in the patent application of William Kirk Wyatt entitled Yarn Separating Means, filed June 17, 1965, Ser. No. 464,797, and assigned to the assignee of the present application, now US. Patent 3,327,462.

In the drawing, the path of the two-ply twisted yarn 18 extends upward from the separation device S to the corner roller 44, then laterally to above the heater 30, and then downward through the second groove 32 of the heater 30 to the twist-barrier device B. To effect the change in direction from upward to lateral, and from lateral to downward, without affecting the twist, three ad justable freely-rotatable rollers 42, 43 and 44 are shown. Each of the rollers 42, 43 and 44 is so disposed angularly that the helix path of the twist is circumferential to the surface of the roller over which it is rolling. When this condition exists, the twist is not disturbed by contact with the roller, and the twisted yarn has the same number of turns per inch when it leaves each of the rollers 42, 43, 44, as it has when it approaches the rollers. Each of the rollers 42, 43, 44 is mounted, by means not shown, to be fully adjustable as to angular and elevational positions.

Heater 30 is an elongated arcuate heater which may preferably consist of an arcuate tube 33 through which steam is passed. The outer forward surface of the elongated tube 33 is provided with a pair of parallel lengthwise grooves 31 and 32. The multi-filament yarn ends 12 and 13 are pulled downwardly in untwisted condition, side by side, throguh the left groove 31 and, after passing through the twist-barrier device B, are pulled upwardly, as a two-ply twisted yarn 18, through the right gro ve 32. The grooves 31 and 32, particularly the groove 32 through which the twisted two-ply yarn is passed, tend to restrain the yarn from migrating laterally relative to the linear yarn path.

Several non-obvious advantages are to be derived from preheating the yarn ends prior to twisting, as will be clear from the following consideration. FIG. 2 is a diagrammatic representation, greatly magnified, which will assist in bringing out the advantages of preheating the multi-filament yarn ends in untwisted condition, prior to twisting. It will be assumed that an arcuate contact heater is used in both instances. When the yarn ends 12 and 13 are in twisted condition, as represented by the twoply yarn 18, shown in the right-hand groove 32 in FIG. 2, the individual yarn filaments follow a helical path, and when the two-ply twisted yarn 18 is pulled up through the heater 30, the plies will roll helically and a particular filament will only occasionally, and perhaps not at all, come into contact with the heated surface of the heater groove 32. In contrast to the twisted yarn filaments, the filaments of the untwisted ends of yarn lie substantially flat, as is illustrated by the filaments in the left groove 31 of FIG. 2, and substantially all of the filaments will contact the heated surface of the heater groove 31 throughout the full length of the heater. Thus, a considerably larger amount of heat is absorbed by the filaments of the untwisted yarn ends 12 and 13 as they are pulled down through the left groove 31 in comparison with the quantity of heat absorbed by the two-ply twisted yarn 18 as it is pulled rollingly upward through the right groove 32.

Pre-heating of the yarn ends, untwisted, as described above, enables the texturing machine to be operated at a substantially higher rate of speed. The percentage increase is greater for the larger denier yarns. For example, in the case of two ends of 70-denier yarn, each end consisting of 34 filaments of .0004" diameter each, it has been found that the texturing apparatus can be operated at a rate of speed fifty percent faster than when the step of preheating the untwisted filaments is not performed.

The heated two-ply twisted yarn 18 is set in the cooling zone C which extends from the upper end of heater 30 to the separation device S. In the drawing, the cooling zone C is merely indicated to be at the ambient temperature of the room in which the false-twisting apparatus is installed. However, to attain maximum allowable speed of operation of my improved texturing apparatus, installation of mechanical cooling means may be necessary, at least in some instances.

In some cases, it may be desirable to insert a known form of tension control device in the path of the untwisted yarn ends between the heater groove 31 and the assembly device B. Such a device is indicated in the drawing by the dot-and-dash rectangle 120. By means of the tension-control device 120, the tension on the untwisted heated filaments in groove 31 may be made relatively low, while keeping a considerable amount of tension on the twisted yarns downstream thereof.

Where the system of the present invention is used in the texturing of a single end of multi-filament yarn, the false twist will be inserted into the yarn at a point downstream from corner roller 44, rather than by the pretwist device 14. Such a device is indicated in the drawing by the dot-and-dash rectangle 121. Use of the separation device 8 will not be necessary, and only one pair of delivery rolls will be required.

What is claimed is:

1. In texturing apparatus:

(a) supply means for supplying at least two single ends of multi-filament heat-settable yarns, said yarn ends at start-up being initially pretwisted to a controlled extent into a two-ply yarn,

(b) delivery means for pulling said yarn ends from said supply means,

(c) separation means upstream from said delivery means for separating the two-ply twisted yarns into single ends,

(d) twist-restraining means upstream from said separation means for inhibiting the twist from running upstream therebeyond,

(e) first contact heater means upstream from said twist-restraining means,

(f) second heater means downstream from said twistrestraining means,

(g) the respective yarns being untwisted in relation to each other and substantially flat during passage through said first contact heater means,

(h) the respective yarns being in a two-ply condition during passage through said second heater means.

2. Apparatus according to claim 1 characterized in that said first and second heater means comprises a single elongated 'arcuate heater having first and second arcuate grooves therein, the untwisted substantially flat yarn filaments passing through said first groove in substantially continuous contact with the surface thereof.

3. Apparatus according to claim 2 characterized in that said elongated arcuate heater is disposed substantially vertically, in that a first cornering roller is provided above the heater for bending the heated twisted yarn about a 90 bend from a vertically upward direction to a generally lateral direction, and in that a second cornering roller is provided laterally from said first cornering roller for bending the twisted yarn about a bend from a generally lateral direction to a vertically downward di rection leading toward the separation means.

4. The method of texturing yarn which includes the steps of pulling two ends of multi-filament yarns with the respective yarns untwisted in relation to each other and substantially fiat and parallel through first contact heater means, assembling the yarn ends into a two-ply twisted yarn, and then pulling the two-ply twisted yarn through second contact heater means.

5. The method according to claim 4 characterized in that the untwisted yarn filaments which are heated prior to assembly into twisted yarn are under relatively low tension, and in that the tension is increased before twisting begins.

References Cited UNITED STATES PATENTS 2,890,568 6/1959 Willens 57-34 XR 2,987,869 6/1961 Klein 57-34 3,192,697 7/1965 Carruthers 57-34 3,270,492 9/1966 Fitton et al. 57-34 XR 3,289,400 12/1966 Scragg 57-34 3,321,904 5/1967 Horvath et al. 57-34 XR 3,355,872 12/1967 Gilcrist et al 57-34 XR 3,395,524 8/1968 Balassa 57-34 3,396,524 8/1968 Parker 57-34 DONALD E. WATKINS, Primary Examiner.

U.S. Cl. X.R. 28-72; 57-106, 157 

